Duplex lapping machine



5 Sheets-Sheet 1 Subwa- H. SLINDGE DUPLEX LAPPING MACHINE FiledlMay 29, 1941 Feb. 16, 1943.

HEREERTENDEE 33M l M Lilus Filed May 29, 1941 5 sheen-'sheet 2 AFf a www5 Feb 16111943 H. s. INDGE i v 2,311,185

DUPLEX LAPPING MACHINE Fl'ed May 29, 1941 5 Sheets-Sheet 3 ffy@ MIU/YIM y HEREER T5 [NEIGE www 941 ,5Msheets-sheet 4 H. S. INDGE DUPLEX LAPPING MACHINE Filed May 29, l

Feb. 16, 1943.

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Feb. 16, 1943.

H. s.4|NDGE DUPLEXYLAPPING MACHINE Filed May 29, 1941 A5 Sheets-Sheet 5 @www Patented Feb. 16, 1943 DUPLEX LAPPING MACHINE Herbert S. Indg'eQWestbormMass. assigner to Norton Company, Worcester', Mass., a

tion of Massachusetts application May ze, 194.1,.seria1Ne. 395,850

c Claims. (ci.` 51x67) The invention relates to lapping machines, and,

more particularly to a multiple spindle lapping machine for simultaneously lapping a plurality of cylindrical work pieces.

One object of the invention is to provide a simple and thoroughly practical lapping. machine for cylindrical work pieces. Another object of the invention is to provide a multiple head machine whereby a plurality of cylindrical work pieces may be simultaneously lapped. Another object of the invention is to provide an automatically con trolled machine for simultaneously lapping a plurality of cylindrical work pieces.

A-further object `of the invention is` to provide a cylindrical lapping machine with a reciprocable type lapping element for lapping` a cylindrical surface on a work piece for a predetermined time interval. Another object of the invention is to provide a lappin-g machiney for simultaneously lapping a plurality of cylindrical Work pieces which is semiautomatic in operation and each head of which is controlled by a single control lever.

Another object of the invention is to provide a multiple' spindle cylindrical lapping machine in which a plurality of lapping heads'are automatically moved toward and from a plurality of work pieces, lappingsticks on each of .the heads are automatically started reciprocating as the `head moves toward the work piece, and in which the work rotation is `automatically initiated by the relative approaching movement of the lapping heads. Other objects will be in part obvious or in part pointed out hereinafter.

The invention accordingly consists in the features of construction, combinations of elements, and arrangements of parts,as will be exemplied in the structure to be hereinafter described,4 and the scope of the application of which will be indicated in the following claims.

In the accompanying drawings in which is shown one of various possible embodiments of the mechanical features of this invention, y

Fig. 1 is a fr-ont elevation of a lapping machine embodying the invention; A

Fi-g. 2 is a left-hand end elevation of the lapping machine as shown in Fig. 1;

Fig. 3 is a diagrammatic showing of the hydraulic and electricalcontrol system;

Fig. 4 is a vertical sectional view, on an enlarged scale, through one of the work heads', showing the headstock and footstock spindles and centers; g

Fig. 5 is a fragmentary vertical sectional view,

taken approximately on the line 5-5 of- Fig. 1,

corpora= showing the fluid motor for' reciprocating the lapping sticks on one of the' lapping heads;

Fig. 61 is a fragmentary front elevation, on an enlarged scale, of the lapping stick holder andl its mounting;

Fig. 4' is a fragmentary'sectional view, taken approximatelyon the line 1 1 of Fig. 6, showing the lapping sticks and holder in an operative posi` tion in engagement with a work piece; and

Fig. 8- is a fragmentary sectional View, on an enlarged scale, taken approximately on the line 8--8'of Fig. 4.

A lapping machine has been illustrated in the drawings, in which a machine base I0 is provided' with* an upper plane surface Il. A plurality of transversely extending T-shaped slots I-2, I3, I4, i5,Y i6 and l-'I are provided. A- plurality of rotatable Work supports are provided on the base i0, each worky supportcomprisin-g a headstock- 2i! and 20a and a footstock '2| and 2id. As/ illustrated in the drawings,- tWo spaced rotatable work supports are provided lout, if desired; the machine may be arranged-to support any number o f heads thereon, as is desired. kThe headstocks 20 and 20a are clamped inpositionon the surface Il of the base l0 by means of al plurality of clamping bolts 22 and` 22a.. y lTwo pairs of bolts are provided on each side of the headstock 20. The clamping bolts 22- and 22a passthr'oughV clearance apertures in theheadstock 240 and .the heads thereof are adjustably Vand slidably positioned within the shaped-slots` I2 andv 3. It will be readily apparent from the foregoing disclosure that the hea-dstock 2'0- may be transversely adjusted as desired. A*

The headstock 2U rotatably supports a spindle 25 in a pair of spacedanti-friction bearingsI 26 and 2l. A multi-step V-groove pulley 218 is mountedon. the outer end of the spindle 2'5. The pulley 2'8 is"y connected by a V-belt. 29 with a pulley 30' mounted on a rotor shaft 3l of an 'electric motor 32'. The' electric motor 32is mounted on a pivotally mounted' supporting plate 3,'3- which is pivotally connected bya rockv shaft 34 with the lieadstock frame.V adjusting screw 35 (Fig.- 1) is provided to facilitate pivotal adjustment of the plate 33150 that the center distance between the pulleys-2`8` and 32.may be adj-usted to ten-sion the drivingN belt- 29 as desired.

The spindle 2'5 is a hollow spindle having a Central borey 3.6 extending therethrough. At one end ofthe bore 3'6 is provided an internal fructoconicalV surface 3,71 which serves to support and locate asleeve 318.- The sleeve 38 may be held in pcsitionby means of a collar 39 whichi's screw threaded onto the left-hand end of the sleeve 38 (Fig. 4). The sleeve 38 serves as a support for a work supporting center y4|). The end of the sleeve 38 is enclosed by an end cap 4| which is provided with a clearance aperture 42 of sucient size to receive the end portion of a work piece 43. A driving member, which in the present case comprises a single gear tooth 44, is adjustably positioned to engage one of the spaces between gear teeth on a gear or pinion 45 formed adjacent to the left-hand end of the work piece 43 (Fig. 4). A single tooth 44 serves as a driving element to rotate the work piece 43 during a lapping operation.

A footstock 2| is adjustably'positioned on the surface I I and is held in adjusted position thereon by clamping bolts I only one of which has been illustrated in Fig. 2. The footstock 2| comprises a footstock base 52 which serves as a support for a pivotally mounted frame 53. A stud 54 pivotally connects the frame 53 with the footstock base 52. The footstock frame 53 is provided with a rotatable spindle 55 which serves as a support for a footstock center 56 which in turn is arranged to engage and support the right-hand end of the work piece 43 (Fig. V4).

In order to facilitate loading of work pieces 43 into the machine, the footstock frame 53 is pivotally mounted so that it may be readily swung to and from an operative position by means of a manually operable lever 51. The lever 51 is iixedly mounted on a pivotally supported member 58 which is pivotally supported by a stud 59 on the footstock base 52. The pivotally mounted member 58 is connected by a stud 68 with one end of a link 6I. The other end of the link 6I is pivotally connected by means of a stud 62 supported on the upper portion of the pivotally mounted footstock frame 53. The member 58 and the link 62 are arranged to serve as toggle levers whereby the pivotally mounted footstock frame 53 may be swung into engagement with an adjustable stop screw 63 and locked in an operative position for a lapping operation. After the lapping operation has been completed, the lever 51 may be readily rocked in a clockwise direction to break the toggle action and swing the pivotally mounted footstock frame 53 together with the footstock center 56 in a clockwise direction to an inoperative position so that the work piece 43 which has been lapped may be readily removed from the machine. Further details of construction of the footstock are not described herein since this footstock constitutes the subject matter of my copending U. S. patent application Serial No. 390,246 led April 25, 1941.

The headstock 20a is identical in construction with the headstock 28, consequently the headstock 20a. has not been illustrated in detail. In

the various figures of the drawings, the same reference numerals suii'ixed with the letter a are used to designate corresponding parts in the headstock 28a. The headstock 20a is similarly adjustably clamped in position on the plane surface I| of the machine by means of clamping bolts 22a the heads of which are arranged to slide within transversely extending T-slots I6 andV I1 to facilitate a transverse adjustment of the headstock 26a.

A footstock 2 Ia is provided having a footstock center 56a arranged to support the opposite end of a work piece supported by the headstock 20a. The footstock *2Ia is identical with the footstock 2|, consequently this footstock will not be described in detail. Like reference numerals apply to like parts suixed with the letter a.

The base I0 also serves as a support for a vertically extending column 65. The column 65 has a lower plane surface which is supported by the upper plane surface II of the base I0. The column 65 is arranged to be clamped in adjusted position on the surface by means of clamping bolts 66 and 61 (Fig. 1), the heads of which ride within the transversely extending T-slots I4 and I5. It will be readily apparent from the foregoing disclosure that the column 65 may be adjusted transversely relative to the base I8 and surface I I to facilitate setting up the machine for a lapping operation. A horizontally extending arm 68 (Figs. 1 and 2) is formed integral with the column 65 and serves as a support for a pair of lapping heads 69 and 10. The arm 68 is provided with a substantially vertical plane surface 1I which serves as a supporting surface for brackets 12 `and 13 of the lapping heads 69 and 10, respectively (Fig. 1). The arm 68 is provided with a pair of parallel horizontally arranged T-slots 14 and 15 by means of which the brackets 12 and 13 may be clamped in adjusted position on the arm 68. A plurality of clamping screws 16 and 11 are provided in the T-slots 14 and 15, respectively. The clamping bolts 16 and 11 pass through elongated slots in the bracket 12 and have their heads shaped to mate with the T-slots 14 and 15, respectively. It will be readily apparent from the foregoing disclosure that the bracket 12 may be readily adjusted longitudinally relative to the column'65 Y' to facilitate adjustment of the lapping head 69 to position it in the desired relationship with a work piece 43 supported by the headstock 20 and footstock 2 I.

Similarly, the bracket 13 may be adjustably clamped in position on the arm 68 by means'of a plurality of clamping screws 18 and 18 which pass through elongated slots in the bracket 13 and have their heads respectively mating with the T-slots 14 and 15. It will be readily apparent from the foregoing that by manipulation of the clamping bolts 18 and 19, the lapping head 10 may be adjusted longitudinally relative to the arm 68 to facilitate positioning the lapping head in the desired relationship with a work piece supported by the headstock 20a and footstock 2 Ia. In order to facilitate loading of work pieces into the machineand removal thereof after a lapping operation has been completed, it is desirable to provide a mechanism for raising and lowering the lapping heads 69 and 10 to and from an operative position. This is preferably accomplished by means of a fluid pressure mechanism such as, for example, an individual fluid pressure piston and cylinder associated with each of the lapping heads. A fluid pressure cylinder 88 is formed integral with the bracket 12. The side face of the cylinder is provided with a dovetailed slideway (not shown) which mates with a correspondingly shaped dovetailed slideway 8| formed on the lapping head 69. A piston 82 is slidably mounted in the cylinder 80 and is connected to one end of a piston rod 83. The upper end of the piston rod 83 is connected to a plate 84 mounted on the upper end of the laphead 69 into an operative position. Theraising V and lowering mechanism for the lapping head 18 is identical with the mechanism for raising and lowering the 'headY 89, consequently this mechanism is not illustrated and described in detail. Like parts are indicated by lilre reference numerals suixed with the letter a.

A iluidv pressure system is provided to-v supply fluid under pressure to raise and lower the lapping heads 89 and 18 as desired. This system may comprise a reservoir 98, preferably located within the base I8 of the machine. Fluid under pressure is drawn from the reservoir 98 by a motor driven pump 9| through a pipe 92 and is forced under pressure through a pipe 93 to a control valve 94. A variable pressure relief valve 95 is connected in the pipe line 93 whereby excess fluid under pressure in the system may be returned directly to the reservoir 98, thus maintaining a desired and predetermined pressure in the system.

The control valve 98l is a piston type valve comprising a valve stem .96 having valve pistons 91 and 98 formed integrally therewith. In the position of the valve (Fig. 3), fluid under pressure passing through the pipe 93 enters a valve chamber located between the valve pistons 91 and 98 and passes out through the pipe 85 into the cylinder chamber 88 to move the piston 82 upwardly to raise the lapping head 69 and maintain it in an inoperative position during a loading operation. During this movement, iluid in the upper chamber of the cylinder 88 exhausts through the pipev 81, through a valve chamber located between the valve piston 91 and an end cap 99 on the end of the valve 94, and exhausts through a pipe |88 into the reservoir 98. A pair of electric solenoids |83 and |84 are provided for shifting the valve stem 99 either toward the left or toward the right, depending upon which solenoid is energized. When it is desired to move the lapping head 69 into an operative position for a lapping operation', the solenoid |83 is energizedv in a manner to be hereinafter described to shift the valve stem 99 toward the left (Fig. 3), thus shifting the valve pistons 91 and 98 so that fluidi under pressure in the pipe 93 entering the chamber located between the valve pistons 91 and 98 passes upwardly through the pipe 81 into the upper cylinder chamber in the cylinder 88 to cause a downward movement of the piston 82 and the lapping head 69 to position it in an operative position for a lapping operation.

During the downward movement of the piston 82 and' the lapping head 69, fluid within the cylinder chamber 88 is exhausted through the pipe 85 into. a valve chamber located between the valve piston 98 and an end cap I8I fastened on the right-hand end of the Valve 94 (Fig. 3) Fluid under pressure in this chamber exhausts through a pipe |82 into the reservoir 98.

A similar control valve 94al is provided for controlling the admission to and exhaust of uid from the cylinder 80a so as to control the movement of the lapping head 18 to and from an operative position. The control valve 84a is identical with the control valve 94, consequently this valve Will-not be described in detail. Corresponding parts will be designated by the same reference numeral sufxed with the letter a.

The lapping heads, as illustrated in the drawings, are arranged so that two spaced cylindrical portions |85v and |86 ofthe work piece 43- may be simultaneously lapped to' the desired and predetermined extent. A lapping stick holder |81 is provided for supporting two pairs of spaced bonded abrasive lapping sticks |88 and |89 (Fig.

6v) for lapping each of the portions |85 and |89,

respectively. The lapping. stick holder |81 is pivotally supported by a pair of oppositely extending trunnions I I8' and II I which are in turn supported by a pair of downwardly extending arms ||2 and I|3. The arms` |l|2 and' |I'3 are fixedly supported' at the lower end of a pivotally mounted member I| 4. The member ||4 is pivotally supported by a stud I I5 which is free to slide vertically relative to the head 69. A roller H8 is'supported by a stud ||1' (Fig. 5) adjacent to the upper end of the member i I9y and is maintained-in operative engagement with a cam |28 by means of a tension spring I I9. The cam and roller are provided so that when the member I|4 is escillated, the cam will produce a slight vertical movement of the pivotally supported member |I4 so that a straight-line reciprocatory movement is imparted to the lapping sticks |88 and' |89 to facilitate a uniform engagement of the lapping elements with the periphery of the work piece during their entire reciprocatory stroke.

A suitable power operated mechanism is provided for oscillating the member I'I4 to reciprocate the lapping sticks |88 and |89 in operative engagement with the spaced portions |85 and |88 of the work piece 43. In the preferred form a self-contained fluid motor |28 is provided comprising a cylinder |2| (Fig. 5) having a piston |22 slidably mounted therein. The piston |22 is connected by means of a piston rod |23 with the upper end of the oscillatable member H8. A pilot valve |24 is slidably mounted within the casing of the motor |28. The pilot valve |24 is provided with a central bore or aperture which contains a slidably mounted shuttle type reversingY valve |25. The pilot valve |24 is provided with a pair of adjustable collars |28 and |21 which are engaged by an upwardly extending portion of the oscillatable member H4 by means of which the pilot valve |24 is automatically shifted at the end of the stro-ke to shift the reversing valve |25 and thereby change the direction of oscillation of the member I4 continuously to reciprocate the lapping sticks |88 and |89'.

Fluid under pressure is admitted through a pipe |28 into the valve mechanism to actuate the piston |22 as desired. An exhaust pipe |29 is provided whereby uid may readily be exhausted from the motor |28 into the reservoir 98. The collars |28 and |21 are preferably adjustably mounted on the valve stem so that the length of the reciprocatory stroke of the oscillatable member and also the reciprocatory stroke of the lapping sticks |88 andV |89 may be adjusted as desired. This hydraulic motor |28 has not been described in detail in the present application, since they details of the motor are not considered to be a part of the present. invention. Any standard motor, either hydraulic or otherwise, might be employed for this purpose. For details of disclosure not contained herein, reference may be had to the prior U. S. Patent 2,212,871 to Wallace H. Wood dated August 27, 1940.

The lapping head 18 is similarly contructed and consequently has not been illustrated in detail. The parts illustrated, however, are identied by the same reference numerals suiiixed by-'theletter a. The lapping arm 18- isfprovided parting a reciprocatory movement to the lapping sticks |0811 and |0911.

It is desirable automatically to start the reciprocatory movement of the lapping sticks |08 and |09 when the lapping head 69 is moved toward an operative position and similarly to stop the reciprocation thereof when the lapping head is moved to an inoperative position. To accomplish this desired result, normally closed valves |30 and |3001 are provided for controlling the nuid motors and |2011., respectively. The valves and |30a may be opened by means of pivotally mounted levers |3| and |3|a, respectively, each having a roller |32 and |32a, respectively. In order that the valves |30 and |30a may be automatically controlled by the approaching and receding movement of the lapping heads 69 and 10, respectively, a pair of cams |33 and |33a are adjustably mounted on the brackets 12 and 13, respectively. The cams |33 and |3311 are arranged to be engaged by the rollers |32 and |3211, respectively, when the heads are moved downwardly toward an operative position to swing the levers |3| and lala'I in a clockwise direction to open the valves |30 and |3011 and thereby automatically to st-art the reciprocatory movement of the lapping sticks |08 and |09 as they move into operative engagement with the work piece to be lapped.

In order that the cycle of operation of the machine may be automatic, it is desirable to provide an automatically actuated mechanism for starting the rotation of the work drive motor 32 in timed relationship with the other parts of the machine. In the preferred form, it is desirable to start the rot-ation of the motor 32 when the lapping head 69 is moved toward an operative position and similarly to stop the work drive motor when the head is moved to an operative or loading position. A rock shaft |35 is supported by the bracket 12. The rock shaft |35 is provided with an adjust-able arm |36, the lower end of which is provided with an actuating roller |31. The roller |31 is arranged in the path of a cam |38 which is adjustably mounted on the vertically movable lapping head 69. An arm |39 is also mounted on the rock shaft |35 and is connected by means of a link |40 to actuate a normally open limit switch |4| when the lapping head is moved toward an operative position. When the cam |33 operates to close the limit switch |4I, it serves to close a magnetic starter switch |42 which receives its power from any suitable source, such as indicated by the power lines |43, to start the work driving motor 32.

Similarly, a rock shaft |3511 (Fig. 3) is mounted on the bracket 13 and is provided witl' an adjustably mounted arm |3611 having a roller |3111 arranged in the path of a cam |38a. The cam |38a is adjustably carried by the vertically movable lapping head 10. An arm |39a is also carried by the shaft |3511 and is arranged so that when the cam |3011 moves downwardly, it rocks the arm |3611, the shaft |3511, and the arm |3911 to close a normally open limit switch |4|a which is in turn connected to close a magnetic starter switch |421z to start the work drive motor 32a for a lapping operation.

A relatively high voltage circuit is utilized through the magnetic starter switches |42 land |4211 to drive the work driving motors 32 and 32a. A pair of transformers |50 and |5011 are 20; the lapping operation. After a predetermined with a similar uid motor |20a (Fig. 3) for improvided for stepping down the current for the remaining control apparatus on the machine.

A push button starting switch |5| is connected in series `with a normally open limit switch |52 which in turn is connected with the solenoid |03. The switch |52 is arranged so that the valve 94 cannot be shifted to move the lapping head 69 downwardly until the footstock frame 53 is swung into operative supporting engagement with the work piece 43. An adjustable electric time delay relay |53 is connected in the circuit and arranged so that it is set in motion when the switch |4| closes on the downward movement of the lapping head 69 toward an operative position. The electric time relay |53 may be any of the standard well known time relays such as, for example, the well known relay known as the Microflex relay manufactured by the Eagle Signal Corporation of Moline, Illinois. The time relay |53 is connected to control the duration of time interval has elapsed, the time relay |53 operates to deenergize the solenoid |03 and energize the solenoid |04 which in turn shifts the valve stem 96 into the position illustrated in Fig. 3 so as to admit fluid under pressure to raise the lapping head 69 to an inoperative position, thus terminating the lapping operation.

A similar push button switch |5|a is provided which is connected in series with a normally open limit switch |5211. The limit switch |5211 is in turn connected with the solenoid |0311 and is arranged so that the push button switch |5|a cannot start an approaching movement of the i lapping head 10 until the footstock frame 53a is moved into an operative supporting engagement with the work piece to be lapped. An electrical time relay |5311 is operatively connected so that when the limit switch |4|a is closed during the downward movement of the lapping head 10 toward an operative position, it serves to govern the extent of the lapping cycle. After a predetermined time interval has elapsed, the time relay operates to deenergize the solenoid |0311l and to energize the solenoid |04a which shifts the valve 94a. into the position shown in Fig. 3 to terminate the lapping operation by admitting fluid under pressure to move the lapping head 10 upwardly to an inoperative position.

A pair of stop switches |54 and |5411, are provided to facilitate stopping the lapping cycle at any time during a lapping operation on either head of the machine. When the push button switches |54 and |5411I are closed, these switches serve immediately to energize the solenoids |04 or |0411., respectively, to shift the valves and thus raise the heads 69 or 'l0 upwardly to an inoperative position, thus terminating the lapping operation, in case it is desired or necessary Vto start the lapping operation before the normal cycle has been completed.

The operation of this machine will be readily apparent from the foregoing disclosure. Assuming the various mechanisms of the machine to have been previously adjusted, a work piece 43 is positioned on the headstock center with the driving tooth 44 engaging a gear space of the gear 45 of the work piece 43, after which the footstock control lever 51 is moved to swing the footstock frame 53or 53a into operative supporting engagement with the center 56 engaging and supporting the footstock end of the work piece. This movement of the footstock to an operative position closes the safety interlock switch |52 so that when the operator desires to stop the lapping cycle, it Vis merel'y Anecessary to close the .push-button `switch |5| to energize the 'solenoid' |03, thus sl'iiftihg the valve 94 so that iluid under pressure lis -admitted to the pipe l81 t'o cause va downward movement of the .piston 82 and the lapping head 69 to lmove the abrasive lapping sticks |08 and |09 into operative engagement with the spaced portions and |06 Aof the workpiece 43 to lap the same.

During the downward movement of the lapping Ahead 69., the roller |32 engages the cam |33 fafterwhi'ch continued movement rocks the valve 'control lever |3| to nopen the valve |30 and thereby start the fluid motor |20, thus starting the reciprocation lof the lapping sticks |08 `and |09. The `downward movement of the lapping head 69 also serves to move the cam |30 into-engagement with lthe actuating roller |31, after which continued movement serves through the arm |36, the rock shaft |35, and the arm |39 'to' close the normally open limit switch |4I. The closing of the limit switch |4| serves to close the magnetic starter'switch |42 to start the Work Ydrive motor 32, thus starting rotation of the work piece 43. At the same time, the closing of the switch |4| serves to set in motion the time delay relay 153 which allows the lapping operation to proceed Vfor a definite and predetermined time interval, after -which the relay trips and ener- 1gli-zes the solenoid |04 to again Shift the control Valve94 'into the position of the parts shown in Fig, 3 to .admit I'fluid under .pressure through the pipe 185 finto the cylinder chamber 86 to cause an upward movement of the piston 32 and the lapping head 69., thus terminating the lapping opi eration, During the upward movement of the lapping head 697 the roller |32 rides up the cam face |33 and allows the lever |3| to swing in a counterclockwise direction to close the ,valve |30, thus stopping the flow of fluid to stop the fluid motor |20, thus terminating the reciprocation of the lapping sticks |08 and '|09.

Similarly, a Work pice `'may be mounted on the headstock center 40a and the footstock frame 53a may then be swung into operative supporting engagement with the center 56a in engagement with the 'Work to support the same for a rlapping operation. The operation of this second lapping head unit is identical with the one just previously described, consequently itis not deemed to be necessary to describe in detail the operation of the second work supporting and lapping unit. While this machine has been illustrated with two work supporting and lapping units, it will be readily apparent that a plurality of units, any

number desired, might be arrangedon a single machine whereby one operator might simultaneously operate and control a 'plurality of lapping operations at the same time.

During the downward movement of the lapping head 69, the roller |32 engages the cam |33, after which continued movement rocks the valve control lever |3| to open the valve |30, thereby to start the fluid motor |20 and thus starting the reciprocation of the lapping sticks |03 and |09. The downward movement of the lapping head 69 also serves to move the cam |38 into engagement with the actuating roller |31 after which continued movementserves through the arm |36, the rock shaft |35, and the arm |33 to close the normally open limit switch |4|. 'Ihe closing of the limit switch |4| serves to close the magnetic starter switch |42 to start the work drive motor 32, thus starting rotation of the work piece 43. At the same time, the closing of the switch |4| serves to -set jin motion the time delay relay |53 which allows the lapping operation to proceed for 7a 'definite and predetermined time interval, after which the relay trips and energizes the solenoid |04 again to vshift the control valve `94 into the -position of the parts shown in Fig. 3 to Yadmit -fluid under ,pressure through the pipe 05 into the cylinder chamber 86 to cause an upward move- .men-t of the :piston 82 and the lapping head 69, thus terminating the lapping operation. During the 'upwardy movement of the lapping head 69, the roller |32 rides up the cam face |33 and allows-the lever |3-| to swing in a counterclock- Wise direction to close the valve |30, thus stopping the flow -of vfluid to stop the fluid motor |20, thus terminating the recip-rocation of the lapping sticks |08 and |09.

Similarly, a work piece may be mounted on the headstock center 40a and the footstock frame 53a may then be swung into operative supporting engagement with the center 56a. in engagement with the work to support the same for a lapping operation. The operation of this second lapping head unit is identical with the one previously described, consequently it is not deemed necessary to vdescribe in detail the operation of the second work supporting and lapping unit. While this machine has been illustrated with two work supporting and lapping units, it will be readily apparent that a plurality of units, any number desired, might be arranged Von 'a single machine, whereby one operator might simultaneously operate `and control a plurality of lapping operations 'at the same time.

-It will thus be seen that there has been provided by this invention apparatus in which the various 'objects hereinabove set forth together with many thoroughly practical advantages are successfully achieved. As many possible embodiments may be made of the above invention and as ma'ny "changes might be made in the embodiment above set forth, it is to be understood that all Vmatter hereinbefoie set, forth or shown in the accompanying drawings is to be interpreted as iiiustr'ativeand not in a inniting'sense.

I claim:

l. In alapping machin-e having a rotatable work 'support including a headstocl; and a footstock, a rotatable spindle lon said headstock, an electric motor to lrotate said spindle, means to move vsaid footstock to and from an operative position, a lapping head including 'a reciprocable lapping stick, means to reciprocate said stick, means including a .piston and cylinder to move said head and stick to and from an operative position, anV electrically actuated control valve to 'control the admission to and exhaust of fluid from said cylinder, and 'an electrical interlock between said -footstock and control valve including a switch actuated `by movement of the footstock to an operative position to actuate said control valve to cause a movement of the lapping head toward an operative position only when the footstock is in an operative position.

2. In a lapping machine having a rotatable work support including a headstock and a footstock, a rotatable headstock spindle supported on said headstock, an electric motor to rotate said spindle, means including a manually operable toggle lever mechanism to swing said footstock to and from an operative position, a lapping head including a reciprocable lapping stick, a iiuid motor on said head to reciprocate said stick, a fluid operated piston and cylinder to move said head and stick to and from an operative position,

a solenoid actuated control valve to control the passage of fluid under pressure to and from said cylinder, and an electrical interlock between said footstock and control valve including a limit switch which is actuated by movement of the footstock to an operative position to facilitate actuation of the control valve to cause a movement of the lapping head toward an operative position only when the footstock is in an operative position.

3. In a lapping machine having a rotatable work support including a headstock and a pivotally mounted footstock, work supporting centers thereon, a rotatable spindle carried by said headstock and supporting said headstock center, an electric motor to rotate said spindle, means including a manually operable toggle lever mechanism to swing said footstock to and from an operative position, a lapping head including a reciprocable lapping stock, a fluid motor on said head to reciprocate said stick,'a iiuid operated piston and cylinder to move said head and stick to and from an operative position, a solenoid actuated control valve to control the passage ofV fluid under pressure to and from said cylinder, an electrical interlock between the footstock and control valve including a switch actuated by movement of the footstock to an operative position to facilitate actuation of the control valve to cause a movement of the lapping head to an operative position only when the footstock is in an operative position, a normally open limit switch actuated by movement of said head to an operative position, and an electrical time delay relay set in motion by said switch .to connism to swing said footstock to and from' an operative position, a lapping head including a Y reciprocable lapping stick, a fluid motor on said head to reciprocate said stick, a fluid operated piston and cylinder to move said head and stick to and from an operative position, a solenoid actuated control valve to control the passage of fluid under pressure to and from said cylinder, an electrical interlock between the footstock and control valve including a limit switch actuated by movement of the footstock to an operative position to facilitate actuation of the control valve to cause a movement of the lapping head to an operative position only when the footstock is in an operative position, a normally open limit switch actuated by movement of said head to an operative position, an electricaltime delay relay set in motion by said switch to control the extent of the lapping operation, a magnetic starter switch which is controlled by said limit switch to start the electric motor when the lapping head moves into an operative position, and a solenoid energized by said time delay to shift the control valve to move the lapping head to an inoperative position.

5. In a lapping machine having a rotatable work support including a headstock and a pivotally mounted footstock, work supporting centers thereon, a rotatable spindle carried by said headstock and supporting said headstock center, an electric motor to rotate said spindle, means including a manually operable toggle lever mechanism to swing said footstock to and from an operative position, a lapping head including a reciprocable lapping stick, a fluid motor on said head to reciprocate said stick, a fluid operated piston and cylinder to move said head and stick to and from an operative position, a valve to control the passage of fluid under pressure to and from said cylinder, a solenoid to shift said valve including a limit switch actuated by movement of the footstock to an operative position so as to move said lapping head toward an operative position, an electrical interlock between the footstock and control valve to facilitate actuation of the control valve to cause a movement of the lapping head to an operative position only when the footstock is in an operative position, a normally open limit switch actuated by movement of said head to an operative position, and an electrical time delay relay set in motion by said switch to control the extent of the lapping operation.

6. In a lapping machine having a rotatable work support including a headstock and a pivotally mounted footstock, work supporting centers thereon, a rotatable spindle on said headstock,

means including an electric motor to rotate said spindle, manually operable means to move said footstock to and from an operative position, a lapping head including a reciprocable lapping element, means to reciprocate said element, means including a piston and cylinder to move said head to and from an operative position, a control valve to control the passage of fluid under pressure to and from said cylinder, an electrical solenoid to shift said valve to move said head to an operative position, an electrical time delay relay which is set in motion by the approaching movement of said head to control the duration of the lapping operation, and a second solenoid which is energized by said relay after a predetermined time interval has elapsed to shift said valve to move said lapping head to an inoperative position.

HERBERT S. INDGE.

Patent No. .2, 511 ,185.

Y CERTIHCATE oF CORRECTION. J

A, February 1.6, `19M vHERBERT s. INDGE. v

It is hereby eertified ,thatl erro-r appears in the printed specifiation of the abdve numbered patent requiring correction as follows/ Page 6,' secnd eolun'm, lines 214.' and 25, strike outthe words "including a limit `switch 'actuated by movement of the feotstoek to an-operative position" and insert the sani'e after "valve" in line 28; and that the said Letters atent should be read with this Correction therein that the` same maf)r conform tol the `:cec-

-ord of the case in the APatent Office.

signed and sealed this 6th" dgy'f--o'f April, A. 1).'19LL5.

Henry Van Arsdale, y(Seal) Acting Commissioner o f Patents. 

